Extension-bit holder



Dec. 6, 192 7.

illnll W. A.,PECK

EXTENSION BIT HOLDER Filed 061,. 26. 1926 OQQOA Illll @wmf Hm I

Patented Dec. 1927.

WILLIAM A. Pncx, or HAVEN, coNNn'orIcU'r.

EXTENSION-BIT nonnen;

' f niapncauon.-meujoctobe; as, Ai926., semaine. 144,382.

v '.Thi's invention vrelates 4to extension bit holders and'moreparticularly to a chuckingy device for extending the effective length ofz. woodbits or thelike .which are'lprovided with tapered rectangularShanks.k t n Il l Anjjimportant ecty of the invention is .to provide adevice of this .character by,

means of which the shank i is securely :j gripped. at its opposite ends,thus preventing any. oscillation of the bitV with relation totheextension. p .y Y

A further object, of the invention lis vto provide a device of thischaracter which is substantially sealed to thereby excludechips orcuttings from entering theV chuck.y and rendering the same inoperative;

A-stillfurther obj ect of the invention is to provide a' device of thischaracter inwhich all Vlikelihood of the chuck becoming loosened duringoperation ofthe drill :is

eliminated. Y i' V A v These and other objectsl attainbythe constructionshown in the, accompanying drawings,'wherein for the purposefofv illus-L tration is shown apreferred embodiment. of

my invention fand wherein Figure 5 is a section on the line v5-5 ofFigure 4.

Referring now more particularly to the drawings, the numeral 10indicates the body of anextension shank provided at one end with means11 whereby it may be engaged in the chuck of a brace or the like. At itsop- 5 posite end, the bodyV is externally screwthreaded at 12 and has areduced axial prolongation, the free'end of which is likewise threaded,as at 14. This threaded end is en.-`

gaged in thel threaded 'bore formedin the lower end of a malleable ironsocket 15. The upper end of this socket is provided with afrusto-pyramidal socket bore 16 for the reception of a frusto-pyramidalshank 17 'of a drill bit. The .chuck 15 is cylindrical in form and hasin its outer surface a v1isingers'dinanyiextelidigfgrammiia'uppi "i poseof which will presentlyappear.` L'

' sndabiy "moundupen 4une reduedek tension 13 iof the extension shankis'aiiut 19, the threads 2 0 V of WhfCh f are adaptedffor ccaction withthethreadsk 12A vat the, upper end of ltheloodyi 1Q. l Theexterior""facecf it 'this nut isknurled for engagemeht'with the handand` adjacent `itskju'pper vendis formed with an annular v groove 211,*Spun into this ygroove at 22jisthelovvernd of the wall of a sleeve23,lt`he interiorV face kof which slidablyfits the exterior faceof the chuck15 and is formedl with" an inwardly' pressed spline key 24 forengagement in the groove 18 of the chuckf Atitsupperend,

the sleeve isformedwith an inwardly vextending flange 25 havingarectangular open",-` ing 26 formed therethrough of a size toi permitpassage of, the shank 17 of' the drill.v

fThis flange at its under surface andintermediate thejends of thefsidefaces, ofthe ,opening 26 'is formed with `notches 27 into which thecornersf ofthe *upper or larger end ofthe frust0-pyramidalbit'"shankj17` may extend. These notches are so positioned that theyalign `with the corners'29 of the frusto-pyrarnidal bore 16 ofthe socketchuck 15, sothat a b'it shank 17 engaged therein will have its uppercorners directed intoL these notches as the chuck 15 moves toward theange 25. In the preferred construction, the faces of the bore 16 and ofthe opening 26 are circumferentially spaced 45 from one another, so thatthe notches 2,7

are located midway the ends of Vthe side walls of the opening 26.

In the operation of the device, to ,insertV a drill bit, the nut 19 isrotated until its threads 20 disengage from the vrthreads 12. Holdingtheextension through the nut, the shank 10 will drop, by gravity, until thechuck 15 is -spaced from the under `sur-face of the flange 25 a distancegreater than the length of the'shank 17 of the drill.` The drill is thenpassed through the opening 26 and engaging the chuck will automaticallyrotate to properlyrseat therein and by this rotation will place the`corners 28 thereof in alignment with the notches 27. The shank l0 isthen engaged withY the hand, with the result that the nut 19 andsleeve'23 will drop until the .threads of the nut 19 engage with thethreads 12. The nut 19 is then rotated y 1 untilV the flange 25 firmlyengages `against the up er end of the shank 17, wedging it gripe'ectually prevents ,any movement whatever on the part of the drill Withrelation to the extension. The nut 19 is made of s less externaldiameter than the sleeveV 23, so that there is no danger of this nutcoming into engagement with the Walls of the `bore formed 'b the'dri'lland being therebyrotated to ree the drill for ,movement in the socket..v,f

v It is lpointed ontf that inthe construction' of drill'bits, While anyendeavor 4is made to have the Shanks thereof "standardized, these shanksdiffer-not only in actual size, butin taper, Withthe result that asocket which will properly' fitione shank will engage an-j other shankeither only at its very end 'or at a y point intermediate 'its ends.Under these conditions, the'shank is free `'to'vvobble in the socket,with the result that crooked boresare formed and bits become'jammed andpossibly broken. Byy providing the Vdouble grip hereinbefore set forth,this 'Wob hlin is entirely eliminated, even though the shan s 17 fail toproperly Iittheshank receiving bore 16.V y

" 4Since the construction herenbefore set forth is obviously capable ofa certain range of change and `modification Without mate# riallydeparting vfrom the spirit of the inventlon, Iv do not limit mysel tosuch specific structure except'as hereinafter claimed.

y I claim y' 'the socketand havingnotches formed in its 1. In anextension holder for drill bits and the like havingfrusto-pyramidalshanks, a socket having a frusto-pyramidal socket boreto receive the shank, a sleeve within, which `the socket .isrlongitudinally shiftable, means holding the socket against. rotationwith relation to .the sleeve, a flange upon Vthe sleeve opposing theopen end of the bore of socketnop Vosing face adapted to receive thecornerso the larger endovv a bit shank en-` gaged in the socketbore,lthe sleeve having Y an opening for inserting'a bitshank.to:the'

socket and means for securing the sleeveand socket in adjusted`P'Osition. f

2. In an extensionhol'der for drillv bits and the like havingfrusto-pyramidal Shanks, a socket having-'a frusto-pyra'midal socketlbore to receive the shank, a sleeve-Within which the socket islongitudinally shiftable,

means holding thesocket ,a ainstrotation with relationy to the sleeve,aange lupon-the sleeve opposing the open end of the bore of the socketand havingnotchesforlned inl its signature.

, WILLIAM A. PECK. i

socket'opposing lface adapted to receive the i"

